prefs: honor settings defined in /etc/gitconfig

Allow falling back to the values defined in /etc/gitconfig when asking
for "global" non-repo settings.

This fixes the ability to define user.email, user.name, cola.tabwidth,
and similar settings in /etc/gitconfig.

Closes #259

Reported-by: Leho Kraav <leho@kraav.com>
Signed-off-by: David Aguilar <davvid@gmail.com>

cola/gitcfg.py

@@ -182,6 +182,13 @@ def read_config(self, path):
 
     def _get(self, src, key, default):
         self.update()
+        try:
+            value = self._get_with_fallback(src, key)
+        except KeyError:
+            value = default
+        return value
+
+    def _get_with_fallback(self, src, key):
         try:
             return src[key]
         except KeyError:
@@ -190,7 +197,9 @@ def _get(self, src, key, default):
         try:
             return src[key]
         except KeyError:
-            return src.get(key.lower(), default)
+            pass
+        # Allow the final KeyError to bubble up
+        return src[key.lower()]
 
     def get(self, key, default=None):
         """Return the string value for a config key."""
@@ -202,6 +211,17 @@ def get_user(self, key, default=None):
     def get_repo(self, key, default=None):
         return self._get(self._repo, key, default)
 
+    def get_user_or_system(self, key, default=None):
+        self.update()
+        try:
+            value = self._get_with_fallback(self._user, key)
+        except KeyError:
+            try:
+                value = self._get_with_fallback(self._system, key)
+            except KeyError:
+                value = default
+        return value
+
     def python_to_git(self, value):
         if type(value) is bool:
             if value:

cola/widgets/prefs.py

@@ -83,7 +83,7 @@ def runner():
 
     def update_from_config(self):
         if self.source == 'user':
-            getter = self.config.get_user
+            getter = self.config.get_user_or_system
         else:
             getter = self.config.get
 

share/doc/git-cola/relnotes.rst

@@ -5,6 +5,11 @@ Fixes
 * We now use bold fonts instead of SmallCaps to avoid
   artifacts on several configurations.
 
+* We now pickup `user.email`, `cola.tabwidth`, and similar settings
+  when defined in /etc/gitconfig.
+
+  https://github.com/git-cola/git-cola/pull/259
+
 * Better support for unicode paths when using inotify.
 
   https://bugzilla.redhat.com/show_bug.cgi?id=1104181